Efect of light on growth of green microalgae Scenedesmus quadricauda: infuence of light intensity, light wavelength and photoperiods

Abstract

Microalgae biomass is a potential source of biomass to be considered as a source of bioenergy, biochemicals and even food supply. The key to an economic and healthy algal cultivation is to optimize the growth conditions. The main objective of this research was to investigate the efects of light on the growth of green microalgae Scenedesmus quadricauda. This wild-type green microalgae Scenedesmus quadricauda obtained from the Porsuk River in the Eskisehir region of Turkey characterized by a high lipid content has been cultivated at diferent wavelengths, diferent light intensities and diferent photoperiod cycles. Our results show that for each light intensity, there is an optimal wavelength. The best performing light intensity was 500 μmol photons m−2 s −1 with a wavelength of 660 nm corresponding to specifc growth rate of 0.621 d−1 and an average biomass productivity of 0.756 g/L following 10 days of growth. When the intensity of the light has been increased to 1000 μmol.m−2.s−1 photons, growth is inhibited by showing signs of photodamage. At an intensity of 100 μmol.m−2.s−1, the growth was either very slow for some wavelengths or no growth for majority of them. This suggests that there is a minimal intensity threshold for growth being specifc for each wavelength. Variable growth performances under diferent light/dark cycles imply necessity of the factor optimization. In this case, a photoperiod of 1: 1 h light:dark mode, with a moderate intensity of 500 μmol of photons m−2 s −1, was the best for an efcient productivity.